The hemisuccinate of cholesterol is described in Example 2 of U.S. Pat. No. 3,657,279. No utility for this compound is disclosed.
U.S. Pat. No. 3,936,478 discloses the use of divalent protective groups including dicarboxylic acid esters such as succinate or glutarate esters to protect the 3-hydroxy group of 24-hydroxycholesterol during dehydration to desmosterol. The divalent protecting groups result in the formation of dimeric compounds.
U.S. patent application Ser. No. 867,204, filed Jan. 5, 1978, inventors Fairney et al, title "1.alpha.,25-Dihydroxycholecalciferol Assay" describes the preparation 1.alpha.-hydroxycholecalciferol-25-hydroxy-hemisuccinate which is utilized as a hapten in the preparation of an antigen which can elicit antibodies selective to 1.alpha.,25-dihydroxycholecalciferol. These antibodies are then used in an immunoassay for this important therapeutic substance. No Vitamin D-like activity, or for that matter, any biological activity is ascribed to the 25-hemisuccinate derivative.
The 3-hemisuccinate of Vitamin D.sub.3 (cholecalciferol) is disclosed by Gemliner, Chem. Abstracts 85:89628m (1976). This compound is utilized as a hapten for the same general purpose (immunoassay) as described immediately above. No biological activity is ascribed to the hemisuccinate derivative.